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California fire clouds

Fires raging over California last week created these towering pyrocumulus clouds – aka “fire clouds.” A close look from jets flying nearby.

Photo credit: James Haseltine and the Oregon Air National Guard 173rd Fighter Wing

Photo credit: James Haseltine and the Oregon Air National Guard 173rd Fighter Wing

These two photographs, taken from an Oregon Air National Guard F-15C on July 31, give a close look at a developing pyrocumulus cloud above the Oregon Gulch fire, a part of the Beaver Complex fire on the Oregon/California border.

Pyrocumulus clouds—sometimes called “fire clouds”—are tall, cauliflower-shaped, and appear as opaque white patches hovering over darker smoke in satellite imagery. Pyrocumulus clouds are similar to cumulus clouds, but the heat that forces the air to rise (which leads to cooling and condensation of water vapor) comes from fire instead of sun-warmed ground. Under certain circumstances, pyrocumulus clouds can produce full-fledged thunderstorms, making them pyrocumulonimbus clouds.

Here’s a satellite view of the fast-moving fires. More than 100,000 acres (400 square kilometers) were charred in a few days as fires raged through forests and grasslands in northern California. NASA’s Terra satellite captured this image on August 2, 2014. Red outlines show where MODIS detected high surface temperatures associated with active burning.